LG K40 (X420ZM) vs LG K51S (K510EMW)
Side by side comparison between LG K40 vs LG K51S phones, differences, pros, cons and full specifications. What's the better?
,
5.7"
IPS
IPS
720x1440
16
MP
MP
8mp
2GB
RAM
RAM
Octa-core
3000
mAh
mAh
(Non removable)
vs
6.55"
IPS
IPS
720x1600
32
MP
MP
13mp
3GB
RAM
RAM
Octa-core
4000
mAh
mAh
(Non removable)
What's the better phone? LG K51S (K510EMW)
The phonemore's choice is much more technical than personal. Therefore, you shouldn't only consider this. Our goal is to help you, but what's important to us may not be important to you. You decide which one is the best! Comment!
5 Advantages 
16 Advantages | 30 Common items in both devices |
| eMMC 5.1 |
| Until 1TB microSD, microSDXC |
| Plastic body, glass front |
| TFT IPS LCD |
| 16 million |
| Only digital zoom |
| PDAF: phase detection autofocus |
| +23 specs and more in the table below |
Check the comparison table below for more items that are not evaluated in comparison score above.
Highlight differences Clear highlight📱 Model features | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Model | K40 (X420ZM) | K51S (K510EMW) |
| Other model names | LG K40 LMX420ZM, LM-X420ZM, LG-LMX420ZM | LG K51s LM-K510EMW, LMK510EMW (Dual-Sim + NFC) |
| Country or region available |  South Africa |   (Europe), (Global, International) |
| Brand | LG | LG |
| Release date | 3/31/2019 | 4/1/2020 |
| Depth | 8.3 millimeters (0.33 inches) | 8.26 millimeters (0.33 inches) |
| Size (width x height) | 71.9 x 153 millimeters (2.83 x 6.02 in) | 76.7 x 165.2 millimeters (3.02 x 6.5 in) |
| Weight | 150 grams (5.25 ounces) | 194 grams (6.79 ounces) |
| Build, materials | Plastic body, glass front | Plastic body, glass front |
| Protection against water and others | MIL-STD-810G military certified: salt, dust, humidity, rain, vibration, solar radiation, transport and thermal shock resistant. | MIL-STD-810G military certified: salt, dust, humidity, rain, vibration, solar radiation, transport and thermal shock resistant. |
📲 Display | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Display type | TFT IPS LCD | TFT IPS LCD |
| Screen size | 5.7" inches | 6.55" inches |
| Screen-to-body ratio | ~76.2% (screen-to-body ratio) | ~81.7% (screen-to-body ratio) |
| Display resolution | 720x1440 pixels | 720x1600 pixels (20:9) |
| Touchscreen | Capacitive Multitouch | Capacitive Multitouch |
| Pixel density (dot pitch) | 282 PPI | 268 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Not supported | Not supported |
| Refresh rate | feature not registered | 60Hz |
| Display features | feature not registered | 400nits[typ] |
🤖 Operating System | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| System version | Android 8.1 Oreo | Android 9.0 Pie |
| Firmware update | feature not registered | feature not registered |
| User Interface | feature not registered | feature not registered |
⚙️ Processor | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Chipset | 64bit: MediaTek Helio P22 (MT6762) (12nm) | 64bit: MediaTek Helio P35 (MT6765) (12nm) |
| CPU | Octa-core, 2 processors: 4x 2GHz ARM Cortex-A53 (Quad-core) 4x 1.5GHz ARM Cortex-A53 (Quad-core) | Octa-core, 2 processors: 4x 2.3GHz ARM Cortex-A53 (Quad-core) 4x 1.8GHz ARM Cortex-A53 (Quad-core) |
| GPU graphical controller | PowerVR GE8320 (650MHz) | PowerVR GE8320 MP2 (680MHz) |
| Performance (benchmark) | feature not registered | feature not registered |
💽 Memory and storage | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| RAM memory | 2GB LPDDR3 | 3GB LPDDR3 |
| Internal storage | 32GB (20GB available) eMMC 5.1 | 64GB (47GB available) eMMC 5.1 |
| External storage | Until 1TB microSD, microSDXC (dedicated slot) | Until 1TB microSD, microSDXC (dedicated slot) |
📶 Mobile networks | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Dual-SIM | Not supported | Dual-SIM Standby - Call active on one sim card (dedicated slot) |
| SIM card | 1 slot (Single-SIM) nano-SIM (4FF) | 2 slots (Dual-SIM) nano-SIM (4FF) |
| Maximum Download / Upload | 300/50 Mbps | 300/50 Mbps |
| Network technology | 2G, 3G, 4G | 2G, 3G, 4G |
| Frequency, bands | Expand band details Collapse details | |
| GSM MHz band | Quad-Band 850/900/1800/1900 | Quad-Band 850/900/1800/1900 |
| Primary 2G network | GSM 850/900/1800/1900 | GSM 850/900/1800/1900 |
| Primary 3G network | UMTS 850/900/1900/2100 | UMTS 850/900/1900/2100 |
| Primary 4G network | LTE Cat6 (Bands 1, 3, 5, 7, 8, 20) TD-LTE (Bands 38, 40) | LTE Cat6 (1, 3, 7, 8, 20) TD-LTE (38) |
| Primary 5G network | Not supported | Not supported |
| Primary data network | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A |
| Secondary 2G network | Not supported | GSM 850/900/1800/1900 |
| Secondary 3G network | Not supported | Not supported |
| Secondary 4G network | Not supported | Not supported |
| Secondary data network | Not supported | GPRS, EDGE |
📷 Camera | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Back camera (main camera) | 16 megapixels | (quad camera) 32 megapixels 5MP ultrawide f/2.216mm1.12μm115° 2MP macro f/2.422mm1.75μm88.6° 2MP depth f/2.41.75μm |
| Main camera resolution | 4608x3456 pixels | 6528x4896 pixels |
| Video recording (primary) | Full HD (1920x1080) 30 fps | Full HD (1920x1080) 30 fps |
| Flash | LED flash on both cameras | LED flash |
| Focal aperture | f/2.0 (aperture) | f/1.8 (aperture) |
| Focal length | feature not registered | 24mm (lens) |
| Sensor size | 1/3" inches | feature not registered |
| Pixel size | 1µm pixel | 0.8µm pixel |
| Autofocus | PDAF: phase detection autofocus | PDAF: phase detection autofocus |
| Touch focus | Supported | Supported |
| Image stabilization | EIS: Digital stabilization | EIS: Digital stabilization |
| Zoom | Only digital zoom | Only digital zoom |
| Face/smile detection | Face detection, Smile detection | Face detection, Smile detection |
| BSI sensor | Not supported | Not supported |
| HDR | HDR photo on both cameras | HDR photo on both cameras |
| Camera extras | feature not registered | feature not registered |
📸 Front camera | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Front camera (secondary) | 8 megapixels | 13 megapixels |
| Front camera resolution | 3264x2448 pixels | 4128x3096 pixels |
| Video recording (secondary) | Full HD (1920x1080) | Full HD (1920x1080) |
| Front flash | LED | Not supported |
| Focal aperture | f/2.0 (aperture) | f/2.0 (aperture) |
| Focal length | feature not registered | feature not registered |
| Sensor size | feature not registered | feature not registered |
| Pixel size | feature not registered | feature not registered |
🔉 Sound and multimedia | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Loudspeaker | Supported | Supported |
| Active noise cancellation | 2 microphones or more | 2 microphones or more |
| Radio | FM | Not supported |
| TV | Not supported | Not supported |
| Video formats | MP4, H.264, H.263, XviD, MKV | MP4, H.265, H.264, H.263, XviD, MKV |
| Audio formats | MP3, WAV, WMA, eAAC+, FLAC | MP3, WAV, WMA, eAAC+, FLAC |
🔌 Connectivity | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| USB | MicroUSB 2.0, USB OTG On-The-Go | USB 2.0 Type-C, USB OTG On-The-Go |
| Audio output | 3.5mm jack | 3.5mm jack |
| TV output | Not supported | Not supported |
| Bluetooth | 5.0 + A2DP/LE | 5.0 + A2DP/LE |
| WiFi | 802.11 a/b/g/n/ac [wifi5] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot | 802.11 a/b/g/n [wifi4] (2.4GHz, 5GHz) WiFi Direct, hotspot |
| DLNA | Not supported | Supported |
| GPS | A-GPS, GeoTagging | A-GPS, GeoTagging |
| NFC | Not supported | Supported |
| Infrared port | Not supported | Not supported |
🧭 Sensors | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Sensors | Accelerometer Ambient light sensor Fingerprint sensor (rear-mounted) Proximity sensor | Accelerometer Ambient light sensor Compass Fingerprint sensor (rear-mounted) Proximity sensor |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Battery type | Li-Ion: lithium-ion (Non removable) | LiPo: li-ion polymer (Non removable) |
| Battery capacity | 3000 mAh | 4000 mAh |
| Charger, watts | Wired charging | 10W (5V/2A) Wired charging |
| Inductive / wireless charging | feature not registered | Not supported |
| Talk time autonomy | 8 hours | 10.5 hours |
| Standby | 100 hours (4.2 days) | 370 hours (15.4 days) |
➕ Other features | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| Call control | Voice dialing, Voice recorder | Voice dialing, Voice recorder, Voice commands |
| Messaging | SMS (T9), MMS, E-mail, Push mail | SMS (T9), MMS, E-mail, Push mail |
| Hands-free calling | Supported | Supported |
| Video calling | Supported | Supported |
| Ringtones | Polyphonic and customized | Polyphonic and customized |
| Web browser | HTML, XHTML, HTML5 | HTML, XHTML, HTML5 |
| Antenna | Internal antenna | Internal antenna |
| Qwerty physical keyboard | Not supported | Not supported |
| Miscellaneous | • Colors: Black, Moroccan Blue, Platinum Gray • 18:9 ratio FullVision display • LED notification • DTS-X Surround sound | • Colors: Titanium, Blue, Pink/Red • Silicone case included • Google Assistant (dedicated side button) • DTS:X 3D audio |
☢️ Radiation rate | ||
| LG K40 (X420ZM) | LG K51S (K510EMW) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | feature not registered | feature not registered |
| SAR 2W/kg (Europe, UK, etc.) | feature not registered | feature not registered |